1. Field of the Invention
Embodiments of the present invention relate to a computer program product, computer system, and method for smart election of a storage module to be excluded when a connection between two storage modules is broken in a mesh storage cluster. In addition, embodiments of the present invention relate to a computer program product, computer system, and method for smart selection of a storage module to be excluded in a mesh storage cluster upon intra-module connection failure.
2. Description of the Related Art
Grid (or “cluster”) storage includes multiple storage modules for providing storage. In a grid based storage system, a cluster topology may be a mesh cluster, especially for a low cost entry level offering for smaller customers and proof of concepts. A mesh cluster may be described as a cluster in which every storage module is directly linked to any other storage module in the cluster.
Each of the storage modules in the cluster is connected to the other in a point to point topology. In an event in which a connection (i.e., an intra-module connection) between any two storage modules is broken (“an intra-module connection failure”), one approach is to exclude one of the two connected storage modules and continue with the rest, N−1 storage modules. This is to avoid a system performance degradation of the cluster because communicating via a third module instead of a direct connection slows system responsiveness and performance degradation as compared to expelling one of the two storage modules from the cluster.
In some cases, the selection of the storage module to be excluded is determined based on the first storage module that complains that there is a broken connection to an adjacent module. A cluster manager excludes the adjacent module. A broken connection indications that the two storage modules cannot transfer data to each other. “Adjacent” may be described as two adjacent storage modules having a point to point connection.
However, in some cases, this approach is not optimized, especially in cases where it is more suitable to exclude the first storage module that complained in order to avoid a performance degradation, for example.